Heat dissipation module

ABSTRACT

A heat dissipation module is provided, including a frame, a base, and a fan. The frame has a depressed portion at an inner edge thereof. The base is connected to the frame and has a bottom surface. The fan is movably disposed on the base and has a plurality of blades. The end of an upper edge of the blades has a first height with respect to the bottom surface. The depressed portion has a second height with respect to the bottom surface, wherein the first height is less than the second height.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority of China Patent Application No. 201620810919.1 filed on Jul. 29, 2016, the entirety of which is incorporated by reference herein.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a heat dissipation module, and in particular it relates to a heat dissipation module comprising a fan on which the height of the blades' upper edges is lower than the outward expansion portion on the frame inlet.

Description of the Related Art

As electronic products are rapidly being developed to have high performance, high frequency, high speed, and a thin profile, the temperature of these electronic products is getting higher and higher. This causes unstable phenomena to occur and thus influence the reliability and the lifetime of the product. Accordingly, heat dissipation has become one of the most important issues regarding electronic products, and a fan module is frequently used in a heat dissipating device.

Referring to FIG. 1A, a conventional fan module includes a frame 10, a motor 11 and an impeller 12. When the motor 11 drives the impeller 12 to rotate and produce airflow from an air inlet to an air outlet (in the direction indicated by arrow A), the heat of the electronic product is dissipated into the environment. However, the air impacts the interior structure of the fan module and produces a noise at specific frequency, which causes discomfort to the users at most of time.

To reduce the noise of the fan module, the fan speed is usually reduced. Referring to FIGS. 1B and 1C, FIG. 1B shows the frequency spectrum of the fan module when the rotational speed is 20000 rpm, and FIG. 1C shows the frequency spectrum of the fan module when the rotational speed is 15000 rpm. FIGS. 1B and 1C respectively show a noise spectrum W1 having a blade frequency W11 at 1700 Hz and a noise spectrum W2 having a blade frequency W21 at 1300 Hz.

It should be known that the noise values L1 and L2 corresponding to the blade frequencies W11 and W21 can reflect the sound quality and the overall noise level. As shown in FIGS. 1B and 1C, the noise value L2 is less than the noise value L1, and which means conventionally the noise peak at the blade frequency can be reduced by a slower rotational speed. However, the heat dissipation efficiency becomes lower as well.

BRIEF SUMMARY OF THE INVENTION

To solve the problems of the prior art, the embodiment of the invention provides a heat dissipation module, comprising a frame, a base, and a fan. The frame has an outward expansion portion at an inner edge of the frame and adjacent to an air inlet of the heat dissipation module. The outward expansion portion forms a depressed structure and has a curved surface or a sloping surface at the inner edge. The base is connected to the frame and has a bottom surface. The fan is movably disposed on the base and is rotatable with respect to the frame. The fan has a plurality of blades. The end of the upper edge of each of the blades has a first height with respect to the bottom surface, and the outward expansion portion has a second height with respect to the bottom surface. The first height is less than the second height.

In one embodiment, the end of the upper edge of each of the blades forms a curved structure.

In one embodiment, the upper edges of the blades are parallel to the bottom surface.

In one embodiment, the frame has a plurality of stationary vanes disposed on an air outlet of the frame and connected to the base. A first angle is formed between the upper edges of the stationary vanes and the bottom surface, and a second angle is formed between the lower edges of the stationary vanes and the bottom surface. The first angle and the second angle are acute angles.

In one embodiment, the first angle and the second angle are the same degree substantially.

In one embodiment, a third angle is formed between the lower edges of the fan and the bottom surface, and the third angle is an acute angle.

In one embodiment, the first, second, and third angles have substantially the same degrees.

In one embodiment, the frame has a plurality of stationary vanes, and the stationary vanes are disposed on the air inlet of the frame.

In one embodiment, the fan has a hub forming a guiding surface on an upper edge thereof, and an outer side of the guiding surface forms a curved or sloping surface.

In one embodiment, the frame, the base, and the fan have metal or plastic material.

In one embodiment, the frame and the base are formed by injection moulding.

In one embodiment, the base has a sustaining portion protruding upwardly.

In one embodiment, the fan has a hub and a shaft disposed at the center of the hub.

In one embodiment, the fan has a sustaining unit, disposed in the sustaining portion to sustain the shaft, and the sustaining unit includes ball bearing, spring, snap ring or bush.

In one embodiment, the fan further has an iron housing, a magnetic element, and a driving unit, the iron housing is disposed in the hub and shaped corresponding to the inside surface of the hub, the magnetic element is disposed in the iron housing, and the driving unit is disposed between the iron housing and the sustaining portion, wherein the magnetic element and the driving unit impel the hub and the blades to rotate.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:

FIG. 1A shows a conventional fan module.

FIG. 1B shows a frequency spectrum of the fan module when the rotational speed is 20000 rpm.

FIG. 1C shows a frequency spectrum of the fan module when the rotational speed is 15000 rpm.

FIG. 2A is a perspective view of the heat dissipation module of an embodiment of the invention.

FIG. 2B is a cross-sectional view of the heat dissipation module in FIG. 2A.

FIG. 2C shows a frequency spectrum of the heat dissipation module when the rotational speed is 20000 rpm.

FIG. 3 is a cross-sectional view of the heat dissipation module according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the appended claims.

Further, spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as being “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the exemplary term “below” can encompass both an orientation of above and below. The apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly.

Referring to FIGS. 2A-2C, FIG. 2A is a perspective view of the heat dissipation module of an embodiment of the invention, FIG. 2B is a cross-sectional view of the heat dissipation module in FIG. 2A, and FIG. 2C shows a frequency spectrum of the heat dissipation module when the rotational speed is 20000 rpm. As shown in FIGS. 2A and 2B, the heat dissipation module of the embodiment comprises a frame 20, a fan 30, and a base 40 connected to the frame 20, wherein a bottom surface 40 a of the base 40 is parallel to the XY plane, and the fan 30 is movably disposed on the base 40 and rotatable with respect to the frame 20. In the embodiment, the frame 20 has a plurality of stationary vanes 21 and an outward expansion portion 22, and the fan 30 has a plurality of blades 31, a hub 32, a shaft 33, a sustaining unit 34, an iron housing 35, and a driving unit 37. Moreover, the base 40 has a sustaining portion 41 protruding upwardly.

As shown in FIG. 2B, the stationary vanes 21 are connected to the inner wall of the frame 20 and the base 40. The stationary vanes 21 are disposed on the air outlet O of the heat dissipation module and for guiding air smoothly downwardly to the air outlet O and exhausting air from the heat dissipation module, wherein a first angle θ1 is formed between an upper edge 21 a of the stationary vane 21 and the XY plane, and a second angle θ2 is formed between a lower edge 21 b of the stationary vane 21 and the XY plane. The first angle θ1 and the second angle θ2 are acute angles having substantially the same degrees. Specifically, the outward expansion portion 22 has a depressed structure with a curved surface formed on an inner side of the frame 20, which is adjacent to the air inlet I to increase the intake and outlet airflow and guide the airflow smoothly flowing into the heat dissipation module, wherein the frame 20 and the base 40 may have metal or plastic material, such as formed by plastic injection moulding. In an embodiment, the stationary vanes 21 can also be disposed only in the air inlet I of the heat dissipation module, or in both of the air inlet I and the air outlet O. Moreover, the outward expansion portion 22 may have a sloping surface to guide the airflow efficiently.

In the embodiment, the fan 30 may have metal or plastic material, and the blades 31 are disposed on the outer side of the hub 32, wherein each upper edge 31 a of the blade 31 has a curved structure. As shown in FIG. 2B, an end 31 c of the upper edge 31 a of the blade 31 is situated on a reference surface P parallel to the XY plane. Specifically, a third angle θ3 is formed between a lower edge 31 b of the blade 31 and the XY plane, wherein the third angle θ3 is an acute angle having substantially the same degrees as the first and second angles θ1 and θ2.

The hub 32 has a substantially round structure, and an outer side on an upper portion of the hub 32 forms a guiding surface 32 a, wherein the guiding surface 32 a is a curved surface to guide more airflow smoothly flowing into the heat dissipation module. It should be understood that the guiding surface 32 a may also be a sloping surface in some embodiments. The shaft 33 is disposed at the center of the hub 32, and the sustaining unit 34 is disposed in the sustaining portion 41 to sustain the shaft 33. The sustaining unit 34 may include a ball bearing, a spring, a snap ring, or a bushing, so that the fan 30 can rotate smoothly. The iron housing 35 is disposed in the hub 32 and shaped corresponding to the inner surface of the hub 32. The magnetic element 36 is disposed in the iron housing 35, such as a flexible magnetic strip having plastic material. The driving unit 37 is disposed between the iron housing 35 and the sustaining portion 41, and it may comprise silicon steel sheets and electronic components, wherein the magnetic element 36 and the driving unit 37 can drive the hub 32 and the blades 31 to rotate and produce airflow.

It should be understood that a first height H1 along the Z direction is formed between the end 31 c of the upper edge 31 a of the blade 31 and the bottom surface 40 a of the base 40, and a second height H2 along the Z direction is formed between the end 22 a of the outward expansion portion 22 and the bottom surface 40 a, wherein the first height H1 is less than the second height H2. As shown in FIG. 2C, a noise spectrum W3 is produced according to the configuration of the aforementioned heat dissipation module, and a blade frequency W31 at 1700 Hz is presented in a noise value L3 (dB).

It should be known that the noise value L3 can reflect the sound quality and the overall noise level. It can be derived from FIGS. 1B and 2C that when the heat dissipation module of the embodiment and the conventional fan module in FIG. 1A have the same rotational speed of 20000 rpm, the noise value L3 (FIG. 2C, at a blade frequency of 1700 Hz) is obviously less than the noise value L1 (FIG. 1B, at a blade frequency of 1700 Hz). In other words, when the fans have the same rotational speed, the heat dissipation module of the invention can reduce the peak value (noise) corresponding to a specific blade frequency of the heat dissipation module.

FIG. 3 is a cross-sectional view of the heat dissipation module according to an embodiment of the invention. As shown in FIG. 3, the heat dissipation module comprises a frame 20, a fan 30, and a base 40. The difference between this embodiment and the embodiment of FIG. 1A is that the upper edges 31 a of the blades 31 in this embodiment are situated on the same reference surface P (as shown in FIG. 3), parallel to the XY plane. It should be noted that a first height H1 is formed between the end 31 c of the upper edge 31 a of the blade 31 and the bottom surface 40 a of the base 40, and a second height H2 is formed between the end 22 a of the outward expansion portion 22 and the bottom surface 40 a, wherein the first height H1 is less than the second height H2. It also can reduce the peak value (noise) corresponding to a specific blade frequency of the heat dissipation module.

In summary, the invention provides a heat dissipation module, including a frame, a base, and a fan, wherein the frame has an outward expansion portion. The fan has a plurality of blades, and an end of an upper edge of the blades has a first height with respect to the bottom surface, and the outward expansion portion has a second height with respect to the bottom surface, wherein the first height is less than the second height. Thus, the airflow can be smoothly guided into the heat dissipation module, and the peak value (noise) corresponding to a specific blade frequency can be efficiently suppressed under the same operation condition when comparing with the conventional fan modules. In other words, the invention can suppress the noise caused by rotation of the fan and make the sound more comfortable to hear, so as to provide users with a better environment.

Use of ordinal terms such as “first”, “second”, “third”, etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having the same name (but for use of the ordinal term) to distinguish the claim elements.

While the invention has been described by way of example and in terms of the preferred embodiments, it should be understood that the invention is not limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements. 

What is claimed is:
 1. A heat dissipation module, comprising: a frame, having an outward expansion portion at an inner edge of the frame and adjacent to an air inlet of the heat dissipation module, wherein the outward expansion portion forms a depressed structure and has a curved surface or a sloping surface at the inner edge; a base, connected to the frame and having a bottom surface; and a fan, movably disposed on the base and rotatable with respect to the frame, wherein the fan has a plurality of blades, the end of an upper edge of each of the blades has a first height with respect to the bottom surface, and the outward expansion portion has a second height with respect to the bottom surface, wherein the first height is less than the second height.
 2. The heat dissipation module as claimed in claim 1, wherein the end of the upper edge of each of the blades forms a curved structure.
 3. The heat dissipation module as claimed in claim 1, wherein the upper edges of the blades are parallel to the bottom surface.
 4. The heat dissipation module as claimed in claim 1, wherein the frame has a plurality of stationary vanes disposed on an air outlet of the frame and connected to the base, a first angle is formed between the upper edges of the stationary vanes and the bottom surface, and a second angle is formed between the lower edges of the stationary vanes and the bottom surface, wherein the first angle and the second angle are acute angles.
 5. The heat dissipation module as claimed in claim 4, wherein the first angle and the second angle have substantially the same degrees.
 6. The heat dissipation module as claimed in claim 4, wherein a third angle is formed between the lower edges of the fan and the bottom surface, and the third angle is an acute angle.
 7. The heat dissipation module as claimed in claim 6, wherein the first, second, and third angles have substantially the same degrees.
 8. The heat dissipation module as claimed in claim 1, wherein the frame has a plurality of stationary vanes, and the stationary vanes are disposed on the air inlet of the frame.
 9. The heat dissipation module as claimed in claim 1, wherein the fan has a hub forming a guiding surface on an upper edge thereof, and an outer side of the guiding surface forms a curved or sloping surface.
 10. The heat dissipation module as claimed in claim 1, wherein the frame, the base, and the fan have metallic or plastic material.
 11. The heat dissipation module as claimed in claim 1, wherein the frame and the base are formed by injection moulding.
 12. The heat dissipation module as claimed in claim 1, wherein the base has a sustaining portion protruding upwardly.
 13. The heat dissipation module as claimed in claim 12, wherein the fan has a hub and a shaft disposed at the center of the hub.
 14. The heat dissipation module as claimed in claim 13, wherein the fan has a sustaining unit, disposed in the sustaining portion to sustain the shaft, and the sustaining unit includes ball bearing, spring, snap ring or bushing.
 15. The heat dissipation module as claimed in claim 14, wherein the fan further has an iron housing, a magnetic element, and a driving unit, the iron housing is disposed in the hub and shaped corresponding to an inside surface of the hub, the magnetic element is disposed in the iron housing, and the driving unit is disposed between the iron housing and the sustaining portion, wherein the magnetic element and the driving unit impel the hub and the blades to rotate. 